Plating apparatus and product thereof



June 5, 192s. "1,672,402" d E. R. vARMSTRONG" PLATING APPARATUS AND P RODUCTTHEREOP Filed oct. 14, v1924. 2 sheets-sheet 1 /m/en for' 2 By h/ls @ffm-wey A June 5, 1928.

E. R. ARMSTRONG PLATING APPARATUS AND PRODUCT THEREOF Filed oct. 14, ,1924 2 eats-sheet 2 a o o I 25 o o o I I. f v 63 7% 60 'I |1||| g' r 12b 6ft: .5@ 72,6? f/fm/ f/mi/ de mmm/wf' Mez yF ,P20 Y- f .m99 v44?(17 5 #af 4a f a' ,y il 4f 44,

48 fm/emor L f. Arm .sfrony 46 46- 15g /7/29 a/or'neg 44 43 43 43 Patented June 5, 1928.

UNITED STATES 1,672,402 PATENT oFFILCE.

EDWARD R. ARMSTRONG, OF HOLLYOAK, DELAWARE, ASSIGNOR T0. E. I. DU PONT DE NEMOURS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OIF DELA.-

WARE.

PLATING APPARATUS ANDY PRODUCT THEREOF.

Application filed October 14, 1924. Serial No. 743,589.

This invention relates to apparatus for the production of continuous metallic strips by the electrolytic deposition of the metal, and to the product/thereof, and, in particular it has to do with apparatus comprising a continuously drivencathode from which the deposited metalis continuously stripped in an endless band, that is, a band of indefinite length. Previous attempts to produce such a band have been unsuccessful, there not having been produced avband satisfactorily free from pitting and other imperfections; this being due, I have found, to failure to maintain the electrodes in proper condition, or maintain the solution in suflicient agitation and free from impurities, or take various other precautions. A further difficulty has been that it was not possible to produce continuous strips of a thickness, width and strength, adapting them for use as con-l tinuous belts of such long span, width andstability as to make them possible for use as casting belts on Which to vdeposit solutions in the making of continuous strips of cellulose-ester materials, for example, nitrocellulose films, by casting and evaporation of solvents. It is an object of this invention to provide an apparatus of the character indicated in which the various priordiiiculties are overcome andy with which strips suitable for use as belts in the field just mentioned can be made. It is also an object to provide such a strip. To these ends, and also to improve generally upon devices of the character indicated, the invention consists in the various matters hereinafter described and claimed. For definiteness, the invention is here describedwith more particular reference to the making of nickel strips or belts, and to the illustrated apparatus, but it will be understood that the invention is not confined to the making of stripsof a particular metal nory to the illustrated embodiment. i

In the accompanying drawings Figure l is a side elevation, partiallyin section, of an apparatus ofthe present invention as a whole;

Figure 2 is a vertical longitudinal sectional View of the electrolytic plating device, but with the cathode drum and its driving means, and certain closely related parts unsectioned and in elevation;

Figure 3 is a plan view of the plating device, and certain closely related parts;

Figure 4 is a fragmental face elevation of the plating drum, or cathode, sectioned in part;

Figure 5 4is a fragmental side view of the rim of the plating drum; 1

Figure 6 is a plan View of the clearing or bubble-removing device;

Figure 7 is a lan view of the rack device for operating t e bubble-removing device,`

yas l and comprising a tank 2 for electrolyte solution, an anode 3 and a cathode 4, a storage tank 5, a filter tank 6 with filters 6 desirably of filter duck, a hard rubber' pump 7 drawing from' the"storage tank, pipe con- Y nections 8 from the storage tank to the filter tank, pipe connections 9, 9, from the filter tank to the tank of the plating device, pipe connections 10 from the plating tank to the storage tank, an overfiow pipe 11, and driving means designated generally as 12 for the cathode and other driven parts. The cathode is in the character of a drum having a inetallic peripherial plating surface or face, and

is partially immersed in the electrolyte in the tank 2. The various tanks may be of wood and the piping of rubber-lined hose with'hard rubber connection. In operation,

as the driving means slowly rotates the cathode 4 (anti-clockwise in the drawing) the metal from the anode is deposited (by way of the solution) on the periphery of the cathodey and is stripped ofi" in .an endless band B; MeanwhileY the solution is continuf ously in agitation and movement and is being continuously cleaned, it being circulated from the tank 2 around the circuit 2--10- 5-7-8-6-9, 9,-2 and being filtered, in the tank 6; any excess in' the tank 6` overflows by the pipe 11 to storage. The tank 2 isdesirably kept closed at the top so far as feasible to prevent the hot vapors fromthe tank reaching the cathode surface and strip. Now to describe in detail certain features of the vplating device :--The tank 2support-s the anode 3 andcathode'4,the latter being journaled by the bearings A14, 14 upon they tank for rotation-upon its axis. \-The anode 3 comprises, in accordance with the invention, a pair'of spaced partitions 15 and 16 reaching across and/supported by the tank.

These partitions are of sheet material of a character to properly withstand the action of the solution, and to not be. plated upon,

'-as phenolic resin (bakelite) or cellulose ester plastic (pyralin) and are each perforated, as at 17, for passage rof the solution. These partitions providebetween them a confining -spaoe -18 within which is received the anode proper.. This consists of pellets 19 of the metal to be deposited, for example, nickel. With this construction the anode can at any timebe conveniently renewed, it merely being necessary to load in pellets at the open ends 182184 of the space 18 as occasion requires. In this way I provide for the replenishing at' will of the metal being plated out, without interruptionof the operation, thus readily permitting the continuous operation which I desire. Desirably 'the 'upper parti- ,upper portions, which are observable at 18a,

18, contain pellets, all danger of there being aconcealedfempty space being eliminated. The positive lead (see Figure 2) may desirably be connected with a bus bar 20 havin projections 21. i

As efore stated/the cathode4 is in the character of a -rotating, drum. f As here shown` it comprises (see Figure 4) an iron (steel) rim 22 fast supported upon the shaft 23 (Figure 3) by the metal arms 24.. At each end the central opening of the cathode is closed solution tight' with a wooden head 25. Carried upon'each head'25'is a peripheral upstandin rim 426, extending throughout the. lengt of the periphery, which serves to conne theA plating. These rims,

are of some material, for example, wood, bakelite or pyralin, unaffected by the bath and upon which thel metal will not plate. For convenience in construction they*l are each inseveral arc-shaped pieces (Figure 5) and in order to ensure that there shall be no creeping. of thesolution along the line` of the joint k27, a pm 28 is tightly driven into the joint which seals the same against-5 creeping of the solution therealong. In further accordance with the inve tion the rims .4

are provided with a series o `closely adjacent arc-shaped protectors 29, closely overhanging the plating surface but suliciently distant therefrom to permit a deposition of the desired thickness. These protectors ex'- tend throughout the circumference of the rim except for such length as it is desirable to provide for the convenient stripping of of the band B, and to provide this length -the protectors are received with a push t in sockets 30 in the rim so that as the drum turns (the movement is slow) they ca in turn be removed to provide the said leng h and then replaced when the need for the length at that particular portion of the rim has passed. These protectors are of a material unaffected by the solution and upon which the metal Will not plate and are desirably of bakelite or pyralin. They serve to prevent treeing of the deposit at the corner 31 between the plating surface and rim. The steel surface of the cathode is desirably plated with copper and then nickel, the same being polished to that degree necessary-to give the finish d-esired on the deposited strip. T-he negative lead is conveniently connected with brushes-and-slipring 32 (Figure 3) contacting the shaft 23 which in turn is in connection with the rim by way of the arms 24. The drive of the cathode is by the heretofore mentioned mechanism 12 to be described in Vdetail hereinafter.

A clearer. or bubble remover 33 is provided. Referring more particularly to Figures 2 and 6, the same comprises the brush bristles 34 held in the hard rubber back or cross bar 35 and extending from side to side across the plating surface and in contact therewith. Desirably the brush is oscillatable about the axis of the cathode to travel over substantially the entire immersed surface thereof, the space 36 between the cathode and the anode partition 15 permitting this. To provide for this oscillation, as here shown the brush is carried between arms 37,

'37 (say, of wood) `each fast at its end to a gea-r wheel 38, loose upon the shaft 23 of the cathode. rack frame 39 (Figure 7) presents two racks 40, 40 eachl in mesh with a respective gear 38. yThe frame is driven (Figure 3) by the pitman-and-crank 41 from the shaft 42 of the driving mechanism -12. With this arrangement the deposit 1s kept free of hydrogen bubblesv and any .suspended impurities and a proper deposit wlthout plts or other imperfections is ensured.

A guide roller 43, preferably of steel oo vered rubber, for the departing finished strip is provided, see Figures 2 and 8. As here shown it extends crosswise the casting surface, parallel and adjacent thereto, being carried by arms 44,44a the one, 44, carried loose upon the shaft 23, and the other fixed v upon the gear-box 12b of the driving mechanism, the gear-box oscillating if the cathyode is to oscillate, and being stationary if' the cathode is not to oscillate, as hereafter described in connection with the drive. The gear-box, and hence the roller, may be held against oscillation by a member 45 (Figure 3) secured to the tank and the gear-box. This roller ensures that the deposited strip will not pre-depart from the casting surface. Conveniently the roller is supported in bearings 46, 46 carried by studs 46a, 46a slidably secured in a cross-piece 47, tension springs 48, adjustable at 49 in the well-understood manner, serving to urge the roller into contact with the band B While permitting yielding on account of irregularities or the like. At each .end of the roller 43 there is carried to rotate therewith Ian edged cutting or marking disc 43a which discs serve to mark oil longitudinally of the band B a straight strip of uniform width.

Desirably, structure is provided for the convenient bufling and cleaning of the plating surface. Thus, as here illustrated (Figure 1)l a pair of swing arms 50, are borne,

one at each side of the tank 2, in4 bearings 51, which arms are ofv a length to bring their bearings 52 into register with the shaft 23 when they are swung to overlie the tank. Thebearings 52 are closable about the sha-ft 23 and when they have been so closed the arms, carrying the cathode, are`swung vback to place the shaft 23 in the pillow blocks 53, in which location the cathode may be dressed or otherwise treated'as desired (as by the polisher P).

The tank 2, at those points where 'the solution supply pipes 9, 9 discharge into the same is shown as provided with a Weir-like foam trap or-trou'gh comprisingthe receptacle 54, baie walls 55 and 56 andlweir wall 57. With this construction the inflowing solutionmust pass the baiiles and flow over the wall 57 before entering the tank 2 proper, Whereforev any foam is prevented from entring the tank; and also the flow is equalize Next lto describe lthe .driving mechanism heretofore designated generally as 12 z-This mechanism comprises (Figures 1, 2 and 9), in its portion which is immediately related to the cathode; devices wherebythe cathode may be given' merely a simple rotation, or may be given a rotation combined with oscillation, the cathode oscillating forward -and back and at the same time slowly advancing. g -z i Carried loose upon the shaft of the cathode is lthe reduction-gear-box 12b containing the reduction train 58-60, 61-62,'6364, 65, of which the driving member is ratchet wheel 58 and the final driven member is the' shaft 23to-which the gear 65 is keyed.

Swinging loose upon the shaft 66, to whichl member 58 and gear 60 are keyed, is a struck 58 to advance the same (clockwise) when the arm 67 swings to the left (in Figure 2). A spring pressed holder pawl 69 is carried on the box 12b to hold the wheel 58 upon retreat of the arm 67. A pitman-and-crank drive 70 drives the arm 67 from the driving shaft 42, the end :of the rod 71 of the pitman-and-crank being pivotably supported by a link 72 loose upon the shaft 23, and having adjacent its so-pivoted end an adjustable striker cam 73 which` at each stroke strikes and swings the arm 67, thus 'advancing the cathode. When the gear-box 12b is held against oscillation, as by the member 45 connecting the gear-box 12 and tank, the motionof the cathode is, evidently, a simple step-by-step rotation. In order, if desired, to combine with this rotation, oscillation of the cathode, it is but necessary to remove the member 45 and bolt the link 72 to the box 12b as by the clamp bolt 74 (see Figure 2 as distinguished from Figure 1). )Vith this change, the rod 71 not only moves the ratchet 58 but also oscillates the gear-box 12". The various meshing or connetted units being 'mounted in the gear-box and the wheel 65 being keyed to the shaft 23, the cathode will be oscillated while at the same time the step-by-step rotation will continue. It will be understood that the sizes and location of the parts are such that even when the gear-box 12b is being oscillated the striker cam overtakes and properly moves the struck arm 67. Desirably the oscillation may be about one hundred degrees. Evidently the roller 43 oscillates with the lcathode, its arm 44a being fast connected with the gear-box. The shaft 42 is shown as driven by the motor 75 through the reduction gear 76. The pump 7 may be driven in timed relation with the other units as by the motor 77, or from the' motor 75.

I am aware that it has been previously proposed to electrolytically deposit metal ,upon a travelling cathode and remove the deposit but, so far as is known, prior devices have` not been capable ofl producing deposits of such quality, stability and thickness as would permit of the production of stripsusable as metal belts for film casting, the excessive thinness (lack of strength) of the deposits and their poor quality, as regards porosity, foreign matter and so 0n, absolutely precluding them .from such use. With the present device, it having provisions as described above for removing bubbles, for constant flow of solution, ready renewal of the anode without interruption of the operation, elimination of foam, and so on, Ii am able to produce heavy, strong, high quality strips Well capable of use for long span belts. These belts find use in, and indeed render possible, the casting ofv cellulose ester solutions into continuous; strips, the belt of present production serving Serial Number 743,590, filed October 14, 1924 entitled Machine for casting composi- ,tion sheets and method 'of making suchY sheets.

As an example of the production of such a strip I givethe following, the Vstrip produced being about 21/2 feet wide, of the great thickness, as compared to previous abortive efforts, of .035 inch and of a length of substantially 120V feet, which could have been indefinitely increased had it been desirable.

Diameter ofpcathode, 4 feet; width of cathode, 2% feet; peripheral speed of cathode4.25` inches per hour; bath, 28 B. solution of nickel sulfate, to which was added' 4 cc. of 100% acetic acid per liter and a dailymaddition of about 1.6 cc. of 7% hydrogen peroxide per liter; solution in system about 575 gallons, and' plating tank maintained substantially full of solution; rate of ilow `through circuit about 40 gallons minute; temperature of bath, 1204300 F.. which was automatically maintained by the` electrical energy used in plating; current density, 57 amperes per square foot givingja. total current of 720 amperes at 9-10 volts; hydrogen ion concentration, very lowJ when starting with a new bath and anode material but as the solution was purified by the peroxide and filters, and as the anode was worked in, the hydrogen ion concentration rose from less than 3.0, to .3.7 at the end ofl siredv film-casting-belt uses.

van

the run; bubble brush oscillation period 10.6 per minute,l the wheel surface being advanced .00667 inch for each stroke; strip produced per day 81/2 feet; time for producing total strip 14 days. To make the strip easily removable from the cathode, after emergence from thebath, the cathode surface was treated with a 0.5% selenious acid solution,'applied withya felt wiper, between the points of stripping and of entering the bath again. During the run the anode was renewed as required by supplying additionall nickel pellets between Vthe confining sheets.z lVith the presentbapparatus strips from .01 to .05 in. thick' and upward can be readily produced, in' widths as great as desired, previous possible strip deposits having at the most ya thickness of .0025`in.-a thickness entirely too small for belts for present de- The present strip has a tensile strength of about seventy to eighty thousand poundsper square inch. Upon completion of-a strip of the desired length it may be smoothed and polished in the usual ways oftheart. In joining the ends of the strip to make a closed belt, the ends may be closed, dove-tailed crosswirse of the strip, and the jointsilver brazed, a riveted-on backing strip being used if desired, and the joint smoothed and polished. Iclaim:v y I per upon rotation of the cathode ,the

. ping Lei/2,402

1. In a lating device, .an electrode resenting a p ating surface and an npstan ing longitudinally extending edge-guarding protion whereby selected .ones of said sections' may be removed to permit unhinderedv removal of the strip deposit from the plating surface. t i p v 3. In a continuous plating machine, in combination, a bath tank, a substantially cylindrical cathode mounted with its axis substantially parallel to the surface of the means comprising a plurality of secf bath and with a portion of its peripherial plating surface immersed in the bath and e the remainder exterior of the bath, whereby plating surface travels into and out of. the bath, an upstanding uarding rim extending (throughout each e ge of the plating surface, and a treeing guard extending along each rim and overhanging the plating surface, B0"

such treeing guard comprising a plurality of adjacentseytions removably received in the rim, vwhereby s aid sections may bere- -moved' from the rim to permit unhi dered stripping of the deposit from the platin sur ace, `and replaced when each selecte portion of the surface has passed the stripoint.' 4. n a continuous plating device, in comibination, a bath tank, a substantial] cylihdrical cathode mounted on said tan to rotate partially immersed therein, and an anode,

comprising an. upper and a lower spaced perforated partition approximately conforming to the curve of said cathode, and a plurality of individual elements of anode .metal received in the space between said 'partitions y and constituting the anode proper, said space having an entrance providlng for the loading in of said anode elements on occasion.

5. In a plating device, inl combination, a

bth tank, electrodes therein, means for supplying solution to said tank, such means comprising a solution discharge device dis'- charging lnto said tank, and means in cooperative relation with said discharge device and tank for equalizingthe iow into the tank. i 6. In a plating device, in combinatioln a bath tank, electrodes therein, means for supplying solution to said tank, such means comprising a solution discharge device discharging mto'said tank, and a. Weir-box device directly receiving the entering solution and -dischargingthe same to the tank.

7. In a plating device, lin combination, a bath tank, electrodes therein, means for supplying solution to said tank, such means comprising a `solution discharge device discharging into said-tank, and a' combined foam-bails-and-weir-box device directly receiving the entering solution and discharging the same to the tank. f

8, In a plating machine, in combination, a rotatable electrode, and-means for rotating said electrode and meanwhile oscillating the same about its axis of rotation.

9. In a plating machine, in combination, a rotatable electrode, means for rotating said electrode, and optionally operative means, cooperative with the rotating means for oscillating the electrode about, its axis of rotation.

l0. In a "plating machine, in combination, a rotatable elect-rode, and means for rotating said electrode and meanwhile oscillating the same, such means-comprising a reductiongearing casing, a` reduction gearing therein, and connectedwith said electrode to rotate the same, means for driving the reduction' gearing, and provisions whereby said driving means may oscillate the reduction-gearing casing thereby to oscillate the electrode during driving of said reduction gearing and rotation of-said electrode.

11.In an assembly for the continuous electrolytic production of metallic strips, in combination, a plating bath tank, a substantially cylindrical cathode rotatably mounted with respect to said tank tohave its peripherial plating surface descend into. and emerge from the bath upon rotation, means associated with said plating surface for coniining the deposit, an anode in said tank and approximately conforming to the curve of said cathode and somewhat spaced therefrom, driven cathode clearing means oscil- 4latable int said space, a solution circuit for discharge of solution into said tank and withdrawal of ittherefrom, driven means for causing said circulation, means associated with 'said tank and solution for preventing foam in said tank; and continuously operating driving means for driving said cathode, for driving said circulation device to 'cause solution to be cleared of .foam by said foam preventing device and to circulate through said tank, and for driving said cathode clearing device, all in timed relation.

In testimony Whereo I aix my signature.

EDWARD R. ARMSTRONG. 

